Hydroforming using a series of reactors



Dec, 9 958 R. w. SAGE 2,863,822

HYDROFORMING USING A SERIES OF REACTORS Filed April 26, 1955 2 Sheets-Sheet 1 RECOVERY Richard W. Sage Inventor es. 9, 11958 R. w. SAGE HYDROF'ORMING usmc A SERIES OF REACTORS 2 Sheets-Sheet 2 Filed April 26, 1955 on NLQE o9 553 9,5 5 29553 $83.56 ne Em 23 o s Em N 09 8N eon DOV Richard W Sage Inventor assaszz and used commercially in operating the non-regenerative hydroforming process. In this type of process the catalyst usually contains the expensive platinum. A good catalyst is one which contains from about 0.5-2% platinum based on the total weight of catalyst carried on an active form of alumina, preferably, the so-called eta form.

2,8fi3,822 Patented Dec. 9, 1958 race The catalyst should also contain a small amount of halogen, say, from 0.2 to 2.0% by weight of the total catalyst composition, of chlorine.

Experiments have shown that this chlorine increases the HYDRDFURMKNG USENG ASERIES F REACTGRS 5 activity of the catalyst by promoting hydrocracking and Richard W. Sage, Fanwood, N. IL, assignor to Esso Rc- PEI-Hilts tha use of a Smaller pefcentage of platinum to Search and Engimmfig Company a cmpomfien GE provide a catalyst of equal activity to that of the catalyst Dela which is halogen-free but contains a greater percentage of platinum. pp l 1955, Semi! 593,989 The object of the invention is to so operate a hydrog mafimsu ((1 forming plant comprising several reactors through which the feed oil passes in series as to cause a proper distribution of halogen on the catalyst, which catalyst is disposed in the several reactors in the form of fixed beds. The present invention relates to improvements in hy- In brief compass, the present invention resides in the droforming. More part cularly, the present invention reconcept of employing a platinum group metal catalyst lates to improvements in hydroforming naphtha in the disposed in a plurality of reactors in the form of fixed presence of a platinum group metal catalyst containing beds through which the feed oil and hydrogen passes in halogen in a non-regenerative type of' operation comseries with reheating between reactors, and rotating pepr sing several steps or stages with reheating between riodically each of the reactors into the lead position so said stages, characterized in that the process is so opthat the catalyst in the reactor in said position acquires erated as to maximize the average halogen content of the halogen from the feed oil and/ or the recycle hydrogencatalyst in the several stages and to provide the highest containing gas to compensate for the halogen lost when halogen content catalyst in that part of the system where the said reactor is not in the lead position. The halogen high halogen content of the catalyst is required. which is usually a chlorine-containing substance is a Hydrofo rm ing is an operation in which a naphtha, natural constituent of many virgin naphthas and the reeither a virgin naphtha, a cracked naphtha, a Fischer cycle gas invariably contains halogen and these sources naphtha or a mixture or" these is contacted at elevated of halogen give out this material to a bed of catalyst temperatures and pressures with a solid catalytic material which has become deficient in halogen. It is pointed out in the presence of added hydrogen. The process is so that a halogen such as chlorine increases the hydrocrackoperated as not to consume hydrogen, and generally, the ing activity of the catalyst and permits the use of less of process results in a net production of hydrogen which, of the expensive platinum group metal within reasonable course, becomes available in an oil refinery for hydrolimits and the combination of platinum or palladium, plus desulfurizing oils, saturating olefins and similar processes. halogen on the catalyst provides a catalyst of high ac- Hydroforming processes may be divided into two gentivity and selectivity, and when properly employed will e ral classes, namely, the non-regenerative type of operapromote the production of high octane gasoline constittion and the regenerative type of operation. In the nonuents in good yields which gasoline will also have good regenerative type of operation the catalyst is utilized volatility characteristics. continuously in the process for an extended period of time In the accompanying drawings, Fig. 1 indicates, dia- UP y months, ll Wing Which the Catalyst is 40 grammatically, an apparatus adapted to permit a multieither regenerated or replaced by fresh catalyst while the stage hydroforming process in accordance with the present plant is off-stream. improvements and Fig. 2 contains a graph drawn from In Contradistinction thereto: in the regenerative yp original data showing the improvement obtainable in the of operation, the catalyst is frequently regenerated, necesactivity of a high eta alumina-base platinum catalyst as Sitafing either a reduction in Plant Throughput o p the chlorine content of the catalyst is increased. p y during regeneration, or the provision f pare Referring in detail to Fig. 1, it will be noted that the or standby reactors to be employed during such regeneraplant there depicted consists of a main preheat furnace tion periods. During regeneration, the catalyst is treated FA d th reheat furnaces F13 FC and 1:1 h 5315. with a regeneration gas, usually containing oxygen, wherer t i four reactors RA, RB, RC and RD through upon carbonaceous deposits are consumed by burning. whi h the naphtha to be hydroformed and the recycled hy- In the non-regenerative P ii is necessary ii) pdrogen gas flow in series, but in accordance with the crate at relatively g Pressures in Order to retard the present invention, each of the four reactors are rotated deposition of carbonaceous and other deactivating bodies i n h of the four positions shown in the drawing by 011 the Catalyst for, of Course, Such d positions seriously manipulation of the valves V. In each of the furnaces impair the activity of the catalyst. Consequently, presthere could be disposed two coils in a single box or case. sures of from 490 to 809 P- as Well as The use Of In operation, the naphtha to be hydroformed together large quantities of so-called recycle gas, i. e., a hydrogenwith hydrogen is passed from 1 through line 2 to the first containing gas obtained from the product recovery sysor preheat furnace FA and thereafter the feed is passed tem and returned to the reaction zone, have been proposed through the reactors according to the below table:

Fm- Re- Fur- Re- Fur- Re- Fur- Ra Star! nace ac'or nace actor nace actor nace actor (1) FA to BA to BB to RB to F0 to R0 to FD to RD Product recovery iii FA to RD to F0 to R0 to FD to BB to FB to RA Product recovery ig FA to R0 to FD to RD to F0 to RA to FB to BB Product recovery ail FA to BB to FB to BA to FD to RD to F0 to RU Product recovery This method of rotation of the reactors is repeated after completion of the cycle of operations indicated above. By this means each reactor is rotated into each of the four positions in a complete plant or system. The main preheat furnace FA is always in the lead position because it has a higher capacity than the reheat furnaces.

The valving as shown in the drawing is adequate for it controls the direction of [low of the oil vapors and hydrogen and for the further reason that the system is not isolated for regeneration with air because the present process is of the non-regenerative type.

In Fig. 2 there is shown the effect of the chlorine content of the catalyst on its activity. This graph is based on a comparison made with a standard catalyst having a relative activity of 100. The curves show that increasing the chlorine content of the catalyst sharply increases the catalyst activity. This means that the amount oi platinum in the catalyst can be reduced provided that a sutlicient amount of chlorine is also present in the catalyst composition.

Analyses of the catalyst from a hydroiorming operation were carried out for 2119 hours in a COtltil'tLOLlN manner under the conditions shown in Table A with the results as to chlorine distribution shown in Table B.

Table A It was found that after running 2119 hours, the catalyst in the several reactors had the chlorine contents shown in Table 13.

Table B Di union of Cltlorin ta. Avg. (1, Cntzily llctt, Wt. l'erevut Reactor No. ltt't. Tierten i I lnltt. Middle 1 Outlet O3 (It) til) i 7-; 41 29 51 -11 33 .38 59 l .119 .32 .36 ll .Eitt

It can be seen that the average chlorine is highest in the first reactor and lowest in the fourth reactor. Furthermore. the concentration of chlorine in passing through any individual reactor is higher at the outlet than at the inlet. The chlorine content of the catalyst at the outlet of the first reactor is essentially that of. the fresh catalyst. This, of course, substantiates the above statement since the average temperature in the first reactor is the lowest, and the outlet of any given reactor has a lower temperature than the inlet because of the strongly endothermic reactions occurring. Thus, it is sta'ulished that the conditions are most favorable for retention of existing chlorine or absorption of additional chlorine in the initial reactor of a given train consisting of: two or more reactors.

The present invention provides a means for maintaining the catalyst in all reactors at a high level of activity in a non-regenerative continuous hydroforming operation by periodically rotating each of the reactors into the lead position whereby chlorine can be absorbed by the catalyst under the favorable conditions existing at this point from the two sources which are described in the following paragraph.

The naphtha feed stock contains chlorine in most cases as a natura ly occurring element in a concentration of 1-5 p. p. m. in an average West Texas naphtha. Further, the gas recycled to the reactor inlet contains gaseous chlorine, a portion oi which is removed from the catalyst and another portion of which has its source in the feed and passes through the system unabsorbed.

i ll Thus, the catalyst in the first reactor has a constant supply of chlorine from which to replenish the chlorine on the catalyst to the equilibrium level. Analyses of the catalyst after extended periods show that an equilibrium chlorine level is reached after a period of time. After reaching this level, rotation of the last reactor into the lead position will build up its chlorine content while the reactor originally in the lead position, now rotated to another position in the reaction train. can fully utilize the activity inherent due to its higher chlo rine content. After a period of time the equilibrium is cestablished and it is necessary to rotate the reactors in the system again. Normally, this rotation would not be required more often than every three or four days depending upon the severity of operating conditions. However, rotation times of one month or longer would still show a substantially higher average chlorine, as indicated in Fig. 2 than operation until the catalyst was completely spent.

Chlorine entering the reaction system above described will be absorbed on the catalyst and increase its activity if the temperature, pressure, and average chlorine on catalyst are such as to favor an equilibrium condition of higher chlorine on the catalyst. in an experiment where chlorine (as con was added to the feed (10-30 p. p. m.) for a short period of time, 0.28 wt. percent of chlorine was absorbed in the system before appreciable excess chlorine appeared at the exit of the unit. During this period of chlorine addition the catalyst activity increased as shown below.

First, the conditions of hydroforming were:

Thus, it is shown that chlorine is taken up by the catalyst at the lower temperature and higher pressure which would prevail in the first reactor. It is pointed out that because of the high catalyst activity at the lower temperature of 912 F" the process possesses greater flexibility, for as activity declines with the passage of time, it is possible to increase the activity by increasing the temperature up to a maximum of about 965 F. without injury to the catalyst. Hence, beginning operations at 9l2 F. gives a permissible temperature range o 53 a l7 F. advan tage over the permissible range where operations must be initiated at 929 This lower temperature at which the catalyst is highly acti e permits a longer catalyst life.

To recapitulate briefly, the present invention relates to improvements in hydrot'orming using a platinum group metal catalyst in a nonu'egenerative type of operation wherein the invention resides in the concept of rota1iny the reactors in a multi-stage hyd eforming operation so that each of the t'eral reactors iJtZC'J. "s the lead reactor whereby reactors which contain cat; t deficien in halogen are replenished with respect to iiili-I important ingredient in the catalyst, the halogen being obtained by the catalyst from the fresh feed .vhich invariably contains halogen and from the recycled ltjt'tlrogetrcontaining gas. Gt course. if it happens that the naphtha feed oil does not contain halogen. or the amount thereof is insufficient, extraneous halogen may be added to the feed in the form of. say, CCh,

As used herein, the term gasifortn signifies the recycled hydrogen-containing gas, the vaporized feed or a mixture of the two.

In the foregoing description and the drawing, there are shown {our reactors. Of course, it will be understood by those who are familiar with this art without departing from the spirit thereof.

What is claimed is:

1. The method of operating a non-regenerative hydroforming process employing a platinum group metal catalyst which comprises providing a plurality of reactors containing the said catalyst, causing a naphtha naturally containing halogen and a hydrogen-rich gas to flow in series through the reactors the lead reactor of said series being maintained at a temperature lower than that prevailing in the succeeding reactors and periodically changing the course of the travel path of the said naphtha and hydrogen through the reactors responsive to the activity of the catalyst in the several reactors by rotating each reactor into the lead position in the series, whereby the halogen content of the catalyst in each reactor is periodically replenished by halogen naturally contained in the feed naphtha.

2. The method set forth in claim 1 in which the highest pressure prevails in the lead reactor.

3. The method set forth in claim 1 in which the catalyst comprises eta alumina, platinum and chlorine.

4. The method of operating a non-regenerative hydroforming process employing a platinum group metal catalyst which comprises providing a system comprising a plurality of reactors containing the said catalyst, causing a naphtha naturally containing halogen and hydrogenrich gas to flow in series through the reactors the lead reactor of said series being maintained at a temperature lower than that prevailing in the succeeding reactors, the eflluent from each reactor being reheated before it enters the next succeeding reactor in the series and maintaining the catalyst at a high level of activity by periodically rotating each reactor into the lead position of the series whereby the catalyst in the reactor newly placed in the lead position has its halogen content increased by adsorption of halogen from the feed naphtha naturally containing halogen entering the system, and the reactor newly removed from the lead position in the series containing a catalyst bed highest in halogen content is rotated into a position Where its higher activity is most effectively utilized.

5. The method set forth in claim 4 in which the platinum group metal catalyst is platinum.

6. The method set forth in claim 4 in which the halo- 1 References Cited in the file of this patent UNITED STATES PATENTS Cox June 16, 1953 Haensel June 26, 1956 OTHER REFERENCES Thermal Transformation of Aluminas and Alumina Hydrates, Stumpf et al., Ind. and Eng. Chem, vol. 42 (July 1950), pages 1398 to 1403. 

1. THE METHOD OF OPERATING A NON-REGENERATIVE HYDROFORMING PROCESS EMPLOYING A PLATINUM GROUP METAL CATALYST WHICH COMPRISES PROVIDING A PLURALITY AS REACTORS CONTAINING THE SAID CATALYST, CAUSING A NAPHTHA NATURALLY CONTAINING HALOGEN AND A HYDROGEN-RICH GAS TO FLOW IN SERIES THROUGH THE REACTORS THE LEAD REACTOR OF SAID SERIES BEING MAINTAINED AT A TEMPERATURE LOWER THAN THAT PREVAILING IN THE SUCCEEDING REACTORS AND PERIODICALLY CHANGEING THE COURSE F THE TRACEL PATH OF THE SAID NAPHTHA AND HYDROGEN THROUGH THE REACTORS RESPONSIVE TO THE ACTIVITY OF THE CATALYST IN THE SEVERAL REACTORS BY ROTATING EACH RE- 